Chapter 1: Problem 45
Multiply. \((\sin \theta-4)^{2}\)
Short Answer
Expert verified
The expansion of \((\sin \theta-4)^2\) is \(\sin^2 \theta - 8\sin \theta + 16\).
Step by step solution
01
Recognize the Formula
The exercise requires us to square a binomial expressed as \((\sin \theta - 4)^2\). We will use the expansion formula of a squared binomial: \((a - b)^2 = a^2 - 2ab + b^2\).
02
Identify Components
In the expression \((\sin \theta - 4)^2\), identify \(a = \sin \theta\) and \(b = 4\).
03
Apply the Formula
Substitute \(a = \sin \theta\) and \(b = 4\) into the formula: \((\sin \theta - 4)^2 = (\sin \theta)^2 - 2(\sin \theta)(4) + 4^2\).
04
Simplify the Expression
Calculate each part of the expression: \((\sin \theta)^2 = \sin^2 \theta\), \(-2(\sin \theta)(4) = -8\sin \theta\), and \(4^2 = 16\).
05
Combine Components
Combine the simplified terms: \(\sin^2 \theta - 8\sin \theta + 16\). This is the expanded form of \((\sin \theta - 4)^2\).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Binomial Expansion
Binomial expansion is a powerful algebraic tool used to expand expressions of the form \((a+b)^n\) or \((a-b)^n\). For squaring a binomial, such as \((a-b)^2\), a specific formula simplifies this process: \[(a - b)^2 = a^2 - 2ab + b^2\]. This formula derives from distributing each part of the binomial across the other — essentially applying the distributive property.
By memorizing these steps, one can quickly and accurately expand any binomial of the form \(a-b\), streamlining complicated algebraic tasks.
- The term \(a^2\) represents the square of the first term.
- The term \(b^2\) represents the square of the second term.
- Finally, \(-2ab\) accounts for twice the product of the two terms.
By memorizing these steps, one can quickly and accurately expand any binomial of the form \(a-b\), streamlining complicated algebraic tasks.
Squaring Trigonometric Expressions
Squaring trigonometric expressions involves raising trig functions to the power of two, most commonly using formulas like \((sin \theta)^2\). In the problem \((\sin \theta - 4)^2\), we apply what we know about trigonometric identities and squares:
When squared, trigonometric values like \(\sin^2 \theta\) often appear in identities, such as \(\sin^2 \theta + \cos^2 \theta = 1\), helping simplify expressions further when combined with other terms.
- First identify the components to be squared: \(\sin \theta\) is the trigonometric expression here.
- Square each component separately as part of the binomial expansion: \((\sin \theta)^2 = \sin^2 \theta\).
When squared, trigonometric values like \(\sin^2 \theta\) often appear in identities, such as \(\sin^2 \theta + \cos^2 \theta = 1\), helping simplify expressions further when combined with other terms.
Simplification of Algebraic Expressions
Simplifying algebraic expressions involves a step-by-step process to make them less complex. This results in an expression that is easier to read and use. For the given expression \((\sin \theta)^2 - 8\sin \theta + 16\), basic simplification techniques include:
The intent behind simplification is to convey mathematical information in its clearest form, aiding further calculations or analysis.
- Combining like terms: Often we see like terms combined to reduce the expression, though in this specific case the terms are distinct.
- Substitute applicable trigonometric identities if they simplify the expression further.
- Check each step: Ensure each calculation follows algebraic rules, preventing potential errors.
The intent behind simplification is to convey mathematical information in its clearest form, aiding further calculations or analysis.